Engine starter drive



April 7, 1959 J. ,1. DIGBY 2,380,619 ENGINE STARTER DRIVE Fild un 27, 1956 INVENTOR. James J A OBNEY ENGINE STARTER DRIVE James J. Digby, Elmira, N.Y., assignor to Bendix Aviation Corporation, a corporation of Delaware Application June 27, 1956, Serial No. 594,289 2 Claims. (Cl. 74-7) The present invention relates to an engine starter drive and more particularly to a drive of the automatically engaging and disengaging type having a yielding driving connection incorporating a compressible elastic element.

It is an object of the present invention to provide a novel starter drive of this type which is simple and economical in construction and efficient and reliable in operation.

It is another object to provide such a device in which traversal and rotation of a drive pinion is accomplished by means of a pin and slot structure which also forms part of the yielding driving connection.

It is another object to provide such a device incorporating a means for positively defining the meshed position of the drive pinion and assisting in maintaining its alignment, which means also serves as a frictional clutch for supplementing the transmission of torque through the yielding driving connection.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing in which:

Fig. l is a side elevation partly broken away and in section of a preferred embodiment of the invention showing the parts in idle position;

Fig. 2 is a similar view showing the parts in cranking position;

Fig. 3 is a of Fig. l; and

Fig. 4 is a detail in perspective of the roll pin which serves as the translating and actuating member for the pinion and sleeve member.

In Fig. 1 of the drawing there is illustrated a power shaft 1 on which a pinion member 2 is slidably journalled for movement into and out of mesh with an engine gear 3. The pinion member 2 is provided with a sleeve 4 formed integrally therewith or suitably fixed thereto, which bears on the power shaft 1. The power shaft is preferably reduced in diameter as shown at 5 to form the bearing for the pinion itself, in order to permit the use of a pinion having a small number of teeth. The outer end of the shaft 1 is preferably supported by an outboard bearing 6.

A driving head 7 is fixed on the power shaft 1 by suitable means as indicated at 8 and 9, and a barrel member 11 is rigidly mounted thereon at one end as indicated at 12. The free end of the barrel is formed with an inwardly extending flange 13, and the pinion sleeve 4 is provided with a radial flange 14 adapted to come into contact therewith when the pinion is fully meshed with the engine gear 3 as shown in Fig. 2. The abutment so provided thus serves to define the meshed position of the pinion, and the flanges 13, 14 also form a clutch for transmitting torque frictionally from the barrel to the pinion during the cranking operation. Preferably a ring 15 of suitable wear-resisting frictional material is interposed between said flanges.

An annular collar 16 is mounted in the barrel 11, hearing on the sleeve 4 of the pinion member. The sleeve section taken substantially on the line 3-3 Patented Apr. 7, 1959 2 Us provided with a spiral slot 17, the barrel 11 is pro vided with an axial slot 18, and a pinion traversing member in the form of a pin 19 is fixedly mounted in the collar 16 with its inner end seated in the spiral slot 17 of the sleeve 4, and its outer end traversing the axial slot 18 in the barrel. It will be understood that a pluralityof circumferentially spaced pins and slots may be provided if deemeddesirable. The pin 19 is preferably of the so called roll pin type as illustrated in Fig. 4 whereby, by virtue of its elasticity, it is firmly held in the collar 16 after being pressed therein.

An annular block 21 of elastically deformable material such as rubber is located in the barrel 11 between the driving head 7 and collar 16, and is normally held under a slight initial compression by engagement of the pin 19 against the right hand end of the slot 18 in the barrel.

In operation, starting with the parts in the positions illustrated in Fig. 1, rotation of the power shaft by the starting motor, not illustrated, in the direction of the arrow is transmitted through the driving head 7 and barrel 11 to the pin 19. The rotational inertia of the pinion member 2 causes the rotation of the pin 19 to traverse the pinion to the right by reason of engagement of the pin in the spiral slot 17, until the travel of the pinion is arrested by engagement of its flange 14 with the flange 13 of the barrel, thus defining the meshed position of the pinion as shown in Fig. 2. Since the forward movement of the pinion is thus arrested, further rotation of the power shaft 1 causes the collar 16 to be moved back against the pressure of the elastic member 21, thereby cushioning the shock of the meshing engagement, and compressing the clutch 14, 15, 13 for the transmission of torque directly to the pinion supplementing the torque transmitted through the pin 19. The frictional connection so provided serves to damp torsional vibrations and prevent premature demeshing of the pinion. The compression of said flanges also reduces the tendency of the shaft 1 to .bend under the lateral force of the cranking load, thereby assisting in maintaining the alinement of the pinion member.

When the engine starts, the overrunning of the pinion causes the pin 19 to return it to idle position where it is yieldably maintained by any suitable means such as a spring pressed detent 22 mounted in the collar 16 and bearing in a groove in the sleeve 4 of the pinion member as illustrated in Fig. 3.

Although certain structure has been shown and described in detail it will be understood that changes may be made in the precise form and arrangement of the parts without departing from the spirit of the invention.

I claim:

1. In an engine starter drive a power shaft, a pinion and sleeve member slidably journalled on the power shaft for movement into and out of mesh with a gear of the engine to be started, a driving head fixed on said shaft, a barrel member fixedly mounted at one end on the driving head, and formed at its other end to provide a stop for determining the meshed position of the pinion; a traversing member having a splined connection with said barrel and an axially-inclined connection with the pinion sleeve, and yielding means positioning said traversing member in the barrel; in which said traversing member is in the form of a pin, and said pinion sleeve is formed with a spiral slot slidably receiving said pin; and including further a collar slidable in the barrel in which said pin is mounted, and said yielding means is in the form of a sleeve of elastically deformable material in the barrel opposing movement of said collar away from the pinion.

2. In an engine starter drive a power shaft, a pinion and sleeve member slidably journalled on the power shaft for movement into and out of mesh with a gear of the engine to be started, a driving head fixed on said shaft, a

barrel member fixedly mounted at one end on the driv- References Cited in the file of this patent ing head, and formed at its other end to provide a stop for determining the meshed position of the pinion; 21 UNITED STATES PATENTS traversing member having a splined connection with said barrel and an axially inclined connection with the pinion 5 1,634,515 Rmgwald July 1927 sleeve, and yielding means positioning said traversing 2,353,904 Jones July 18, 1944 member in the barrel, in which said barrel is formed at its 7 2 355 934 Fitzgerald Aug 29 1944 3 i g gg j g gf fl? iffgfl igji g f j gj 5 2,602 335 Mill r uly 8, 1952 p p g g 2,635,470 Lewis Apr. 21, 1953 pinion to frictionally clutch the pinion to the barrel and 10 to assist in maintaining the alignment of the pinion. 2,635,471 LEWIS P 21, 1953 

